Electric Resistance Welding Tubing
Unidus Tube&Supply can supply ERW tubes according to tubing manufacturing standards like ASTM A513 type-1 & -2 or equivalent to meet customers requirements.
ERW tubing can be an ideal choice for structural applications, where dimensional tolerances are not critical. This tubing with appropriate modifications in mechanical properties can be used for bending, flattening, flaring or other types of fabrication applications. ERW tubing is available in a wide range of wall-to-diameter ratios and can be manufactured from Hot rolled/ Cold rolled steel.
Drawn Over Mandrel Tubes (DOM)
DOM steel tubing is manufactured from electric resistance welded (ERW) tubes, followed by cold drawing over a mandrel and through a die. This process improves:
- Inside and outside diameter accuracy
- Surface finish (ID & OD)
- Mechanical properties
- Concentricity
- Wall thickness uniformity
Our products can be applied across multiple industries:
| Tube Type |
Main Application Areas |
Typical Applications |
|
ERW Tubes
|
Boilers |
Water tube boilers, fire tube boilers, economizers, superheaters |
| Heat Exchangers |
Shell and tube heat exchangers, condensers, oil coolers, air coolers |
| Power Plants |
Thermal power plants, waste heat recovery systems, industrial boilers |
| Industrial Equipment |
Heat transfer equipment, pressure vessels, process equipment |
|
DOM Steel Tubing
|
Automotive Components |
Transmission shafts, steering columns, suspension components, axle tubes, drive shafts, camshafts |
| Hydraulic Systems |
Hydraulic cylinders, jack sleeves, hydraulic components |
| Mechanical Applications |
Bushings, machined parts, structural components, precision assemblies |
Quality
1. Manufacturing procedure for ERW Tubing
Tubes are manufactured from mild steel strips slitted from Hot Rolled Low Carbon Steel coils. The strip passes through a series of drive forming and fin rolls and takes the required circular shape and is welded continuously by passage of an electric current of high frequency.
2. Manufacturing procedure for DOM Tubing
ERW Tube → Cold Drawing → Mandrel Drawing → Heat Treatment →Straightening → Inspection → Cutting
DOM tubing is an ideal solution for applications requiring tight tolerances, high concentricity, and consistent wall thickness, especially for precision machining and structural components.
FAQ
1. What is ASTM A214 tube?
ASTM A214 is welded carbon steel tubing for boilers, superheaters, and heat exchangers.
2. What is ASTM A178 tube?
ASTM A178 is low carbon steel tubing used for heat exchangers and condensers.
3. What is welded & cold drawn tube?
It is welded tube further processed by cold drawing to improve tolerance and surface finish.
4. Are these tubes suitable for U bending?
Yes, welded & cold drawn tubes are ideal for U bend applications.
5. Do you test weld seam quality?
Yes, we perform eddy current and other NDT testing.
6. What is DOM tubing?
DOM tubing is ERW tubing cold drawn over a mandrel to improve dimensional accuracy and surface finish.
7. Is DOM tubing seamless?
No, DOM tubing is welded tubing that is cold drawn for precision performance.
8. What standard is DOM tubing?
ASTM A513 Type 5 and Type 6 are the most common standards.
9. What are DOM tubes used for?
DOM tubes are used for hydraulic cylinders, shafts, automotive components, and machined parts.
10. Can DOM tubes be machined easily?
Yes, DOM tubes are ideal for precision machining.
